GeezerVison

Also, I've noticed related warning:

Python/optimizer.c: In function ‘_PyJit_translate_single_bytecode_to_trace’:
Python/optimizer.c:600:11: warning: operand of ‘?:’ changes signedness from ‘int’ to ‘unsigned int’ due to unsignedness of other operand [-Wsign-compare]
  600 |         ? (int)(target_instr - _Py_INTERPRETER_TRAMPOLINE_INSTRUCTIONS_PTR)
      |           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

I'm going to merge this as it's a minor but important fix and I have an approval. Sorry Mark if you want to review it. We can make any further changes in your PR that comes with the switch-case for trace recording.

JFTR, I don't know much about the perfomance implications of this PR.
But I'm sure that it's a clean fix with a correct test.

Well, I don't know the exact perf implications either. However, the implication is the following:

1. Currently, when we hit another ENTER_EXECUTOR (ie another executor is seen), we end with _DEOPT.
2. _DEOPT goes back to the interpreter, and does not link executors.

Meanwhile, _EXIT_TRACE links executors. So if we see an ENTER_EXECUTOR and end with an _EXIT_TRACE, we end up linking from the first executor to the executor at the exit.

For Jitted code, the benefits of staying in jitted code without going from jit -> interpreter -> back to jit is enormous. It's one function call with lots of register moves.

Yes, I understand the purpose of this change. Meanwhile, thanks for the detailed clarification.